| 年份 | 尼日尔  | 
                                                            
|---|---|
| 2023 | - | 
| 2022 | 0.162615 | 
| 2021 | 0.164707 | 
| 2020 | 0.167476 | 
| 2019 | 0.167653 | 
| 2018 | 0.165059 | 
| 2017 | 0.162868 | 
| 2016 | 0.160654 | 
| 2015 | 0.157996 | 
| 2014 | 0.155431 | 
| 2013 | 0.153228 | 
| 2012 | 0.150622 | 
| 2011 | 0.148008 | 
| 2010 | 0.146132 | 
| 2009 | 0.144557 | 
| 2008 | 0.143367 | 
| 2007 | 0.142481 | 
| 2006 | 0.141682 | 
| 2005 | 0.140792 | 
| 2004 | 0.139802 | 
| 2003 | 0.138651 | 
| 2002 | 0.137327 | 
| 2001 | 0.135917 | 
| 2000 | 0.13431 | 
| 1999 | 0.132581 | 
| 1998 | 0.13067 | 
| 1997 | 0.128661 | 
| 1996 | 0.126674 | 
| 1995 | 0.123856 | 
| 1994 | 0.120354 | 
| 1993 | 0.116856 | 
| 1992 | 0.113358 | 
| 1991 | 0.10971 | 
| 1990 | 0.105649 | 
| 1989 | 0.101336 | 
| 1988 | 0.0968309 | 
| 1987 | 0.0922674 | 
| 1986 | 0.0876387 | 
| 1985 | 0.0828118 | 
| 1984 | 0.0778726 | 
| 1983 | 0.0725743 | 
| 1982 | 0.0670505 | 
| 1981 | 0.0618466 | 
| 1980 | 0.0572407 | 
| 1979 | 0.0532517 | 
| 1978 | 0.05017 | 
| 1977 | 0.0481592 | 
| 1976 | 0.0465295 | 
| 1975 | 0.0447356 | 
| 1974 | 0.0427024 | 
| 1973 | 0.0402836 | 
| 1972 | 0.0373383 | 
| 1971 | 0.0343422 | 
| 1970 | 0.0318598 | 
| 1969 | 0.029949 | 
| 1968 | 0.028846 | 
| 1967 | 0.0285594 | 
| 1966 | 0.0285401 | 
| 1965 | 0.0285243 | 
| 1964 | 0.0283824 | 
| 1963 | 0.027966 | 
| 1962 | 0.0273305 | 
| 1961 | 0.027037 | 
| 1960 | 0.0277245 |